Meet Oscar, the last of five daughters born to General François Augustin Regnier de Jarjayes, the Commander of the Royal Guards. Raised by her father as if she were a boy, Oscar undergoes rigorous military training from an early age with the aim of eventually taking command of the Royal Guards serving at Court after her father retires. At fourteen years old, Oscar is assigned to protect Marie Antoinette upon her arrival at the French Court. Despite being brought up as a man and dressing in male attire, Oscar openly identifies as female. She embraces her femininity while using her male position to gain freedoms that she could not have achieved as a lady of the court.
Oscar's romantic interests include André Grandier, her servant at the Jarjayes mansion and later a soldier in her regiment, as well as Marie Antoinette, whom she serves as a bodyguard. Rosalie Lamorlière also falls in love with Oscar, who affectionately refers to her as her "spring breeze." Despite disliking court intrigues, Oscar remains at the French Court out of loyalty to her father and her friend, Marie Antoinette. At one point, Oscar develops feelings for Fersen, a man who is forbiddenly in love with Marie Antoinette.